Coupling



FIG. 1 is a top perspective view of the coupling;

FIG. 2 is front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a bottom view thereof; and,

FIG. 7 is a top view thereof.

The broken lines shown in the drawings depict an environment that forms no part of the claim. 

CLAIM We claim the ornamental design for a coupling, as shown and described. 